Conventional bicycle frames have been built from individual tubes which are secured together by welding or other fastening means to make up a composite frame assembly. Such tubes are relatively heavy, having been made by extrusion or by rolling and seaming of a metal alloy.
Conventional bicycle frames also may be of the monocoque type wherein the structural support is provided by a stressed outer skin assembled over internal stiffening ribs and other structural elements. Monocoque frames may have aerodynamic advantages over conventional tubular frames due to the aerodynamic shape and unitary nature of the outer skin.
Conventional tubular frames and conventional monocoque frames both have the disadvantage of requiring the fastening together of numerous structural pieces that are expensive to make and assemble. For example, monocoque frames require the assembly of a large number of structural support elements, including shear webs, reinforcing angles, reinforcing blocks and strips, and joining blocks. There support elements must then be covered by a stress carrying outer skin. One such monocoque bicycle frame is described in U.S. Pat. No. 4,513,986 issued Apr. 30, 1985.